Recent developments in implantable pacemakers have included providing a memory means in the pacemaker for controlling characteristics of a tissue stimulation pulse. In order to enhance flexibility of such programmable pacemakers, means have been developed to transmit parameters or control signals to be stored within the pacemaker memory means and verify control signals stored within the memory means as well as other parameters such as voltage, temperature, etc., transmitted from the pacemaker. Conventional means for transmitting signals from the pacemaker to an external receiving means have typically utilized some sort of amplitude modulation scheme, although it has long been known in the communications art that frequency modulation is less susceptible to noise than amplitude modulation. However, FM/FM or FM/AM systems have not been widely utilized in implantable tissue stimulators because of the power required to generate and transmit these types of telemetry signals. The present invention provides both an FM/FM and FM/AM telemetry system for a living tissue stimulator system which greatly reduces power required from an implanted power source.